Pressure actuated fuze



Oct. 6, 1964 2 Sheets-Sheet 2 Filed March 12, 1963 2958a Gama N 6t PETER D EVANOFF JOHN E WROTE 4', JR.

INVENTORS fmzggw AT RNEY;

5, 1964 P. D. EVANOFF ETAL 7 PRESSURE ACTUATED FUZE 2 Sheets-Sheet 1 Filed March 12, 1963 PETER D EVANOFF JOHN E WROTE 4, JR.

INVENTORS 3,151,557 PRESSURE ACTUATED FUZE Peter D. Evanolf and John F. Wroten, .lr., Baltimore, Md, assignors to The Bendix (Torporation, Baltimore, Md", a corporation of Delaware Filed Mar. 12, 1963, Ser. No. 264,621 Claims. (ill. 102-70) This invention relates to arming devices and more particularly to a fuze which is armed and fired in response to changes in barometic pressure.

A need has arisen for a fuze which can be armed at a high altitude and which can be relied upon to the at a somewhat lower altitude, but an altitude which is considerably above the launch altitude. Such a fuze should be as safe as possible for personnel, requiring only normal handling prior to launching, and preferably, should not impose serious limitations on storage time or require elaborate check-out procedures, such as are common with electrically actuated devices using batteries, wiring or electrical contacts. It is also desirable that the fuze be simple in design, highly reliable and comparatively inexpensive to produce. We have found that a snap-acting diaphragm which responds to atmospheric pressure differentials can provide sufiicient energy to operate an arming device and also to fire a primer charge. By using the ambient atmospheric pressure on the ground prior to launch as the reference pressure, no significant energy is stored in the devices. The pressure differentials required for arming occur only at substantial altitudes far distant from operating personnel or equipment. It is, therefore, an object of the present invention to provide an air pressure responsive fuze which is highly reliable in operation.

It is another object of the present invention to provide an air pressure operated fuze which requires no elaborate handling or check-out procedures.

It is another object of the present invention to provide an air pressure operated fuze which. imposes minimum restrictions on storage life or storage conditions.

It is a further object to provide a barometrically operated fuze which is comparatively inexpensive to produce,

eing readily manufactured, assembled and tested.

It is a further object to provide a barometrically operated fuze which is light in weight and in which the eifect of acceleration or G forces is minimized.

Other objects and advantages will become apparent from consideration of the following specification taken in connection with the accompanying drawing in which:

FIG. 1 is a cross-sectional view of our barometrically operated fuze device with the parts shown in safe position; and

FIG. 2 is a cross-sectional view of our barometrically operated fuze device with the parts shown in armed position.

Referring now to FIG. 1, a generally cylindrical housing member is shown at numeral 10. Housing It) includes a flange 12 which receives a plurality of screws 14 for attaching an end plate 16. An additional flange 18 receives screws 20 for attaching a diaphragm assembly including a snap-acting diaphragm 22 supported at its periphery by means of a ring-shaped member 24. Extending across the interior of the cylindrical. housing member It) is a somewhat irregularly shaped wall 26 which includes an axially directed cylindrical portion 27 defining a channel and having an end portion 28 substantially closing said channel at one end. A firing pin 36 is fastened to the snap-acting diaphragm member 22 and passes through the interior of the channel section 27. A bellows member 32 having a very low spring rate is attached to wall 26 by means of a fluid tight seal shown at numeral 34. At its opposite end, bellows 32 is effec- Patented Got. 6, 1964 "ice tively sealed to the diaphragm 22 by means of a threaded washer member 36 which acts in conjunction with a nut 38 to fasten tightly together along the firing pin the upper part of bellows 32, a sealing member 46 which may be a washer of rubber or other suitable resilient material, the center of diaphragm 22 and a washer 42. Also threadedly engaged with firing pin 30 is a calibrated spring retainer member 44 whicheffectively closes the lower end of the channel portion 27 and retains a calibrating spring 46 under a desired compressive force. A nut 48 is shown threadedly engaged with firing pin 36 at its lower end.

Positioned on end plate 16 is a bracket 50 which carries a piv'ot 51 supporting a lever 52. Lever 52 is shown as hearing against a primer carriage 54 which is movable from left to right in a channel 56 and which includes a port 57 carrying a primer charge 58. A small depression 59 shown on the surface of the primer carriage 54 receives the point of firing pin 30. A resilient member 60 fastended to a boss on the end plate 16 includes a small projection 61 at its left end. A port 62 is located in end plate 16 in axial alignment with firing pin 60.

A small port 63 in wall 26 provides communication between the reference pressure chamber 64 and atmospheric pressure. Positioned in this port is a valve member 66 which is adapted to seal against a small O-ring 68. Valve member 66 is urged toward its closed position by means of a coil spring 70 operative between the under surface of wall 26 and a flange 72. Valve member 66 also includes a passage 74 which, as shown, is in alignment with a passageway 76 in the side of housing 10, a passageway 78 in an extension of wall 26, passageways St in spring retainer member 44 and a passageway 82 in the firing pin 36. Passing through all of these aligned passageways is the safety pin 86 which prevents movement of the firing pin or closing of valve member 66 until it is removed from the housing.

After manufacture and assembly, the device will leave the manufacturing facility and will be stored in exactly the condition shown in FIG. 1. Prior to launch, removal of the safety pin 86 will cause the reference pressure valve 66 to close under the urging of spring 70, thereby trapping atmospheric pressure in the chamber 64. With this arrangement, no pressure differential occursacross the diaphragm until the safety pin is removed and therefore no energy is stored in the fuze. After launching, the pressure on the upper side of the diaphragm 22 will gradually decrease with increasing altitude. When the desired altitude, as established by the calibration of the device is reached, diaphragm 22 will suddenly snap to the position shown in FIG. 2. It then carries firing pin upwardly. stretching bellows 32 somewhat and causing nut 48 to contact the inner end of lever 52, moving it upwardlyand causing this lever to rotate in a counterclockwise direction around pivot 51, As thislever rotates,

its lower end pushes the primer carriage 54 toward the right which is freed to move in this direction with the withdrawal of firing pin 30 from the depression 59.

. Carriage 54 will travel until it hits the stop at the end of channel :56, when projection 61 drops into depression 59 and prevents any further movement or rebound toward the left. Thus the port 57 and the primer charge 58 are held in axial alignment with port 62. Further increases in altitude have no additional effect on operation of the assembly.

Upon descent, the air pressure above diaphragm 22 increases until, at some altitude lower than the arming altitude, the pressure differential across diaphragm 22 I is insufiicient to hold the diaphragm in the position shown in FIG. 2 and it snaps back inwardly, driving the firing pin 30 into the primer charge.;58 and causing the force of the resulting discharge to be directed through the aligned ports 57 and 62 Where it ignites another charge (not shown).

It will be appreciated from the foregoing that applicants have devised a very simple, yet reliable and accurate barometrically operated fuze. The amount of force available from a snap-acting diaphragm is limited, yet it has been found sufiicient to actuate both the arming and firing cycles without further power amplification means. The diaphragm itself has reached a state of development such that the pressure differentials required to effect operation in either direction are both predictable and consistent, thus assuring accuracy. The fuze would normally be stored with the saftey pin in place, thereby avoiding the storing of energy by assuring that ambient pressure acts against both sides of the diaphragm. This would be absolutely required for air transportation, of course. Even if the safety pin is inadvertently removed on the ground prior to launch, arming is most unlikely to occur because the slight pressure differentials experienced at a given location on the ground are far short of those required to cause the diaphragm to snap out. This differential is also sufliciently great to provide reasonable assurance that the diaphragm will not be actuated from any normal jars or bumps occurring during handling. Storage life is excellent in that no batteries or electrical contacts are included and even mechanical joints or journals that could corrode or bind are substantially eliminated.

Although only one embodiment has been shown and described herein, modifications may be made within the scope of the present invention.

We claim:

1. A barometrically actuated fuze comprising a cylindrical housing member, a wall located internally of said housing member including an axially disposed channel forming part of said wall, a flange at one end of said channel, and an end plate covering one end of said housing member, said end plate having a port in substantial alignment with said channel;

a snap-acting diaphragm covering the opposite end of said housing;

an elongated firing pin carried by said diaphragm and extending into said housing in alignment with said port;

a bellows member having one end sealed to said wall and its other end movable with said diaphragm and said firing pin;

a spring retainer fastened to said firing pin and positioned within said channel;

a spring positioned in said channel between said spring retainer and said flange;

a primer carriage arranged for limited movement along the inside face of said end plate, said carriage including a depression and a port, said depression positioned to be in alignment with said firing pin when the fuze is in safe position and said port positioned to be in alignment with said firing pin when said fuze is in armed position, said port being adapted to receive a primer;

a bracket mounted on said end plate and a lever supported by said bracket, one end of which is in contact with said primer carriage and the opposite end being positioned to be engaged and moved by said firing pin when said diaphragm is actuated outwardly by decreasing pressure outside of said housing thereby causing said primer carriage to be moved to the armed position; and

a primer carriage retainer including a resilient member having a projection adapted to be positioned in said depression when said carriage is in the armed position.

2. A barometrically actuated fuze as set forth in claim 1 wherein said wall includes a port and a spring loaded valve is positioned in said port.

3. A barometrically actuated fuze as set forth in claim 1 2 wherein said spring retainer member, said spring loaded valve and said housing all contain channels capable of alignment, and a pin is removably positioned in said channels to block any actuation of said firing pin and to keep said spring loaded valve from sealing against its seat until said pin is removed.

4. A barometrically operated fuze comprising a housing of substantially cylindrical shape;

a wall located internally of said housing member including an axially disposed channel forming part of said wall and a flange substantially closing one end of said channel;

a snap-acting diaphragm overlying one end of said housing and cooperating therewith to form a chamber;

a firing pin carried by said diaphragm and extending through said channel and said flange;

sealing means including a resilient member providing a gas-tight seal between said housing and said diaphragm adjacent said firing pin;

an adjustable spring retainer member fastened to said firing pin effectively closing the opposite end of said channel;

a spring positioned in said channel between said spring retainer and said flange;

a primer carriage including a port and a primer charge in said port arranged for movement relative to said firing pin such that when said carriage is in a first position said port is out of alignment with said firing pin and when said carriage is in a second position said port is aligned with said firing pin, and

lever means movable in response to movement of said diaphragm for moving said carriage from said first position to said second position.

5. An air pressure operated arming device as set forth in claim 4 wherein an orifice is positioned in said housing providing communication between ambient air and the interior of said chamber, and valve means are provided for closing said orifice.

6. An air pressure responsive arming device as set forth in claim 5 wherein a removable safety pin is provided for preventing movement of said firing pin to its armed position and for holding said valve means open until said safety pin is removed.

7. A barometrically actuated fuze comprising a housing; a chamber forming part of said housing including a snap-acting diaphragm overlying one end of said chamber, a bellows having one end sealed to said housing and its opposite end effectively sealed to said diaphragm;

a firing pin attached to said diaphragm;

a resilient member operatively positioned between said diaphragm and said housing;

a primer carriage including a port and a primer in said port arranged for movement relative to said housing, said port being positioned on said carriage such that in the safe position of said fuze, said port is out of alignment with said firing pin and when in the armed position of said fuze, the port is aligned with said firing pin,

lever means movable in response to movement of the diaphragm caused by decreasing pressure exterior of said chamber for moving said primer carriage from safe to armed position;

and means retaining said carriage in armed position when said diaphragm is again moved in response to increasing pressure outside of said chamber.

8. An air pressure operated arming device compirsing a housing;

a chamber forming part of said housing including a snap-acting diaphragm overlying said chamber,

a firing pin attached to said diaphragm and movable therewith;

sealing means including a resilient member providing a gas-tight seal between said housing and said diaphragm adjacent said firing pin;

a Primer Carriage including a P and a Primer charge 10. An air pressure responsive arming device as set in Said P arranged for movement relative to Said forth in claim 9 wherein a removable safety pin is profifing P Such that when said carriage is in a fi vided for preventing movement of said firing pin to its position said port is out of alignment with said finng armed position and f holding Said valva means open pin and when said carriage is in a second position, 5 until said safety pin is removed said port is in alignment with said firing pin, and

lever means movable in response to movement of said References Cited in the file of this atent firing pin for moving said carriage from said first posip tion to said second position. UNITED STATES PATENTS 9. An air pressure operated arming device as s t f rth 2,513,185 Lauritsen June 27, 1950 in claim 8 wherein an orifice is positioned in said ho 2, 01,245 Bowersett June 24 1952 ing providing communication between ambient air and the 2,845,902 Ackerman et a1. July 1953 interior of said chamber, and valve means are provided for closing said orifice. 

8. AN AIR PRESSURE OPERATED ARMING DEVICE COMPRISING A HOUSING; A CHAMBER FORMING PART OF SAID HOUSING INCLUDING A SNAP-ACTING DIAPHRAGM OVERLYING SAID CHAMBER, A FIRING PIN ATTACHED TO SAID DIAPHRAGM AND MOVABLE THEREWITH; SEALING MEANS INCLUDING A RESILIENT MEMBER PROVIDING A GAS-TIGHT SEAL BETWEEN SAID HOUSING AND SAID DIAPHRAGM ADJACENT SAID FIRING PIN; A PRIMER CARRIAGE INCLUDING A PORT AND A PRIMER CHARGE IN SAID PORT ARRANGED FOR MOVEMENT RELATIVE TO SAID FIRING PIN SUCH THAT WHEN SAID CARRIAGE IS IN A FIRST POSITION SAID PORT IS OUT OF ALIGNMENT WITH SAID FIRING PIN AND WHEN SAID CARRIAGE IS IN A SECOND POSITION, SAID PORT IS IN ALIGNMENT WITH SAID FIRING PIN, AND LEVER MEANS MOVABLE IN RESPONSE TO MOVEMENT OF SAID FIRING PIN FOR MOVING SAID CARRIAGE FROM SAID FIRST POSITION TO SAID SECOND POSITION. 